Objective:To evaluate the feasibility and validity of great auricular nerve preservation during parotidec-tomy.
Methods:Thirty patients with parotid tumors were ran-domized to 2 groups. Sixteen patients (group A) under-went classic parotidectomy with sacrifice of the great au-ricular nerve. The surgeon tried to spare the nerve in the 14 patients (group B). Tactile sensitivity, pain sensitiv-ity, and tactile discrimination were evaluated preopera-tively and at 7 days, 30 days, 6 months, and 12 months after surgery. The regions examined were the superior helix, lobule, and infra-auricular and posterior auricu-lar regions.
Results:After surgery, both groups showed lower levels of sensitivity, mainly in the lobule and in the infra-auricular region. These alterations were less pronounced in group B. Both groups showed improvement over time. In group B the tactile sensitivity reached preoperative lev-els by 6 months after surgery. The recuperation in group A was partial and stabilized at 6 months after surgery. Conclusion:Great auricular nerve preservation is tech-nically feasible during parotidectomy, with a decrease of the sensitivity alterations in the early postoperative pe-riod and avoidance of the permanent sequelae that oc-cur when the nerve is sacrificed.
Arch Otolaryngol Head Neck Surg. 2002;128:1191-1195
T
HE GREATauricular nerve (GAN) is usually cut at the level of the parotid infe-rior pole during a paroti-dectomy and many au-thors find this procedure inevitable.1-4 Surgeons who are involved in this type of surgery are familiar with the sensitive al-terations in the operated area, a frequent complaint by the patient. Traditionally, little importance is given to this sequela and it is considered a small price to be paid for the removal of the main disease.5But there are reports in the literature of com-plications due to hyposensitivity in the lob-ule region after parotidectomy.6,7In recent years, we have seen an in-creasing concern not just in cure rates, but also in the functional results of all types of surgical treatment, including parotid surgery. The idea of GAN preservation is not new,8-10 but it has not been widely accepted. There are arguments over its vi-ability and validity. To clarify these ques-tions, we performed a prospective ran-domized study.
The GAN is a sensitive nerve that has its origin in the second and third spinal nerves.8It becomes superficial in the
pos-terior border of the sternocleidomastoid muscle. From there, it ascends to the pa-rotid region where it splits. The nerve di-vision pattern is important to the surgeon who intends to preserve it, and this subject was the secondary aim of this study.
PATIENTS AND METHODS PATIENTS
From October 1995 to October 1997, patients about to undergo a parotidectomy without pre-operative diagnosis of malignant tumor were divided in 2 groups. Group A (16 patients), un-derwent a classic parotidectomy and the GAN was sacrificed. In group B (14 patients) an at-tempt was made to preserve the nerve during the surgery.
The age and sex of the patients, size and location of the tumor, and histopathologic re-sults were used to evaluate the comparability between the groups.
The average age for all patients was 47 years, ranging from 16 to 78 years. Group A had a mean age of 50 years (range, 27-73 years); group B had a mean age of 43 years (range, 16-78 years). There were 20 female patients, 13 in group A and 7 in group B.
Concerning the size of the lesions in all patients, 6 were less than 2 cm in diameter From the Department of
(group A, 5; group B, 1), 13 were between 2 and 4 cm (group A, 6; group B, 7), and 11 were more than 4 cm (group A, 5; group B, 6).
Tumors in the inferior parotid pole were present in 19 cases, 9 in group A and 10 in group B. In 5 patients, all in group B, there were extensions to the deep lobe of the parotid, and a total parotidectomy was necessary. In the other cases, a superficial parotidectomy was done. In all cases, the facial nerve and its branches were preserved.
The duration of the surgical procedure was recorded, as were the GAN branches that were preserved and their ana-tomic distribution.
The postoperative histopathologic examination revealed 27 benign lesions (14 pleomorphic adenomas, 2 monomor-phic adenomas, 5 Warthin tumors, 2 lipomas, 1 hemangioma, 1 cystic lesion, 1 chronic inflammatory process, and 1 hyper-plasic lymph nodule).
In 3 patients, the final diagnosis revealed a malignancy. The first case, a lower grade acinic cell carcinoma, had preop-erative cytological examination findings that suggested a pleo-morphic adenoma. The second case, a fibrosarcoma, had 2 in-conclusive preoperative fine-needle aspiration biopsies. The third case, an intraparotid metastasis of a breast cancer, had a cyto-logical study that suggested an adenoma. The first 2 patients underwent postoperative radiotherapy and the third patient was referred to clinical oncology.
Nine cases of pleomorphic adenoma, 1 case of monomor-phic adenoma, 3 cases of Warthin tumors, and the heman-gioma case were in group B. The rest of the tumors, including the 3 cases of cancer, were in group A.
GAN PRESERVATION TECHNIQUE
The skin incision starts at the infra-auricular area and is limited to the superficial subcutaneous layer. A blunt dissection is done at the sternocleidomastoid muscle posterior border until the GAN trunk is identified. The nerve is dissected upward and usually 3 branches can be visualized: an anterior branch that goes to the parotid parenchyma and preauricular skin, a posterior superfi-cial branch that goes to the auricle, and a posterior deep branch
that goes along the anterior border of the sternocleidomastoid muscle. The anterior branch is usually sacrificed. The last 2 branches can be technically preserved during the surgery. Occa-sionally an inferior anterior branch is identified and it can be pre-served. The anatomy of the GAN is demonstrated inFigure 1A. With the main trunk and the posterior branches protected, we proceed with the parotidectomy. We had no major problem in preserving the posterior branches of the auricular nerve, even in big tumors, since these branches do not go to the tumor. They run vertically and can be preserved by careful dissection when the fascia connecting the parotid gland to the sternocleidomas-toid muscle is cut (Figure 1B).
Tactile sensitivity in the superior helix, lobule, and infra-auricular and posterior infra-auricular regions was evaluated during preoperative examination and 7 days, 30 days, 6 months, and 12 months after the surgery. The superior helix was defined as the superior one third of the auricle. The lobule was defined as the inferior part of the auricle without cartilage. The posterior auricular area was defined as an area between the posterior au-ricle insertion and the hairline. The infra-auricular area is lo-cated between the auricle and the angle of the mandible. Tactile sensitivity was evaluated using cotton wool, which was gently applied at least 3 times in each of the 4 areas. The patient, with eyes closed, would give a signal if he or she felt the cotton. Pain sensitivity was evaluated by touching the 4 areas, sometimes us-ing a pointed instrument, sometimes with a blunt instrument, and recording the patient capacity to identify the right stimulus with the eyes closed. Tactile discrimination was evaluated us-ing a 2-point discriminator. We started with a 3-cm distance and decreased 1 cm each time, until the patient was not able to iden-tify the difference between a 2- and a 1-point touch. The results for tactile and pain sensitivity range from 0 to 3 depending on the percentage of right stimulus identification, with 0 represent-ing the worst result and 3 the best result. The tactile discrimi-nation results represent the shorter distance between the 2-point sensation that the patient can discriminate. When the patient was not able to discriminate a 3-cm distance, a grade of 4 was given. So, 4 represents the worst result and 1 the best result.
The average results for each group were obtained and a comparative analysis was done.
A B Anterior Branch Posterior Superficial Branch Posterior Deep Branch Main Trunk Anterior Inferior Branch
RESULTS
The sacrifice of the GAN anterior branch was necessary in all group B patients. In 1 case the posterior superfi-cial branch was also sacrificed, preserving the posterior deep branch. In all other cases, it was possible to pre-serve both the superficial and the deep posterior branches of the GAN. The anterior inferior branch was preserved in the 2 cases where it was identified.
The mean duration of surgery in group A was 118 minutes, ranging from 70 to 180 minutes. In group B the mean duration was 121 minutes, ranging from 80 to 180 minutes.
There were 11 cases of postoperative temporary fa-cial nerve paresis, 5 in group A and 6 in group B. All pa-tients had complete recovery of this motor deficit.
Two patients in group B presented infra-auricular area hyperesthesis 6 months after surgery. During the first year of follow-up, no patient complained of Frey syn-drome or had local recurrence.
The results of the preoperative and postoperative sen-sitivity evaluations are shown inFigures 2,3, and4.
COMMENT
The unnecessary sacrifice of anatomic structures is not justified, mainly if it implies significant dysfunction. Be-sides the discomfort provoked, the postparotidectomy hyposensitivity of the lobule has been associated with traumatic lesions secondary to deficiency in defense mechanisms mediated by pain.6,7Another frequent com-plaint is the difficulty in wearing earrings.
Theoretically, the preservation of the GAN would avoid such complications. But to actually confirm the va-lidity of the procedure, we have to answer some ques-tions: First, whether preservation of the GAN is techni-cally feasible during parotidectomy and, second, whether the preservation is associated with any undesirable fac-tor, such as prolonged surgical time, a higher tumor re-currence rate, or any other complication. Finally, we need
to know if the preservation of the GAN is really related to better functional results. This work was undertaken to an-swer these questions.
Our 2 groups in the present study were similar with regard to age, size of the lesions, and extension of the inferior parotid pole. Group A had more female patients and group B had all the cases of deep parotid lobe ex-tension.
In all but 3 cases the final histopathologic study con-firmed the preoperative diagnosis of a benign lesion. The cancer cases were in the group in which the GAN was sacrificed. For this reason it is not possible to evaluate the preservation of the GAN in malignant tumors.
Most authors describe 2 branches of the GAN, an anterior one and a posterior one.8As we observed, at least 3 branches were identified: (1) an anterior branch that directs to the gland, whose preservation in all our cases was not possible. (2) One branch is superficially poste-rior and goes to the auricular lobule. It runs a high risk of being cut if careful dissection is not done. (3) The last branch is deeply posterior, located along the anterior bor-der of the sternocleidomastoid muscle, and goes to the posterior auricular area. In a few patients it is possible to identify a fourth branch that is inferior and anterior and is located at a lower level than the limit of the infe-rior parotid. Its preservation is possible during paroti-dectomy (Figure 1). The present study showed that the preservation of the 2 posterior branches is technically fea-sible and, in group B, it was posfea-sible in all but 1 patient whose posterior superficial branch was sacrificed. Even large tumor located in the inferior part of the parotid does not avoid the preservation of the posterior branches of the auricular nerve.
There was no major difference in the operative time between group A and group B. The main factor affecting the surgery duration was facial nerve dissec-tion. The identification and preservation of the GAN took 5 to 10 minutes. The occurrence of temporary facial nerve paresis was similar in both groups, despite the fact that all 5 cases of total parotidectomy were in 1.0 0.5 0 Preoperative 7 d 30 d 6 mo 1 y Pain Sensitivity 1.0 0.5 0 Preoperative 7 d 30 d 6 mo 1 y Posterior Auricular Superior Lobule Infra-auricular Area
group B, involving a procedure with a greater manipu-lation of the facial nerve.
Late occurrence of infra-auricular hyperesthesis was found in 2 group B patients, but without causing major discomfort. The absence of complications such as Frey syndrome and recurrence probably is due to the 1-year limited follow-up. We did not intend to evaluate the in-cidence of Frey syndrome in this study. We have not rou-tinely done starch iodine testing. But, it was interesting to notice that, during the first year of follow-up, none of our patients complained of Frey syndrome. After this pe-riod, some patients developed this syndrome.
Seven days after the surgery, both the tactile and pain sensitivity showed worse results compared with the pre-operative evaluation. This occurred in all regions, but mainly in the lobule and infra-auricular region. The fact that we tested areas such as the superior auricular area and the posterior auricular area may give an idea of too good results. These areas had not much sensitivity change
by the nerve sacrifice. If we limit our analysis to the lob-ule and the inferior auricular area, a greater postopera-tive change in the sensitivity will be noticed.
The decline in sensitivity was greater in group A. After 30 days, the results improved in both groups, but were still better in group B. At the 6-month postopera-tive evaluation, the results in group B reached the pre-operative level. In group A, there was still a sensitivity deficit that tended to stabilize and remain the same at the 12-month postoperative evaluation.
There was some difficulty in evaluating the tactile discrimination. Many patients had a preoperative 2-point discrimination of 2 cm or higher and a 4-cm evaluation was not possible because it would have gone beyond the limits of the researched regions. Despite these prob-lems, we noticed a difference in favor of group B. At the 7-day postoperative evaluation, both groups showed worse discrimination compared with preoperative results, mainly in the lobule and infra-auricular region. The results for 3.0 2.5 2.0 1.5 1.0 0.5 0 Preoperative 7 d 30 d 6 mo 1 y Tactile Sensitivity A 3.0 2.5 2.0 1.5 1.0 0.5 0 Preoperative 7 d 30 d 6 mo 1 y B Posterior Auricular Superior Lobule Infra-auricular Area
Figure 3. Tactile sensitivity after auricular sacrifice (A) and after auricular nerve preservation (B). 0 Represents the worst result and 3 the best result (see the “Patients and Methods” section for more detailed explanation).
3.5 2.5 4.0 3.0 2.0 1.5 1.0 Preoperative 7 d 30 d 6 mo 1 y Tactile Discrimination A B Posterior Auricular Superior Lobule Infra-auricular Area 2.5 3.0 3.5 4.0 2.0 1.5 1.0 Preoperative 7 d 30 d 6 mo 1 y
not result in significant increase in operative time and is not associated with major complications. Preservation of the GAN decreases the early postoperative sensitivity defi-cit and avoids the permanent sequelae that occurs when the nerve is sacrificed. Therefore, the routine sacrifice of the GAN during parotidectomy should be avoided, mainly in cases of benign disease.
Accepted for publication March 11, 2002.
Corresponding author and reprints: Mauro Becker Mar-tins Vieira, MD, Avenida do Contorno, 9215 / Sala 802, CEP 30.110-130, Belo Horizonte MG, Brazil (e-mail: [email protected]).
4. Saunders RJ, Hirata RM, Jaques DA. Salivary glands. Surg Clin North Am. 1986; 66:61-85.
5. Rankow RM, Polayes IM. Complications of surgery of the salivary glands. In: Conley JJ, ed. Complications of Head and Neck Surgery. Philadelphia, Pa: WB Saunders Co; 1979:196-214.
6. Brown AMS, Wake JC. Accidental full thickness burn of the ear lobe following division of the great auricular nerve at parotidectomy. Br J Oral Maxillofac Surg. 1990;28:178-179.
7. Fardy MJ. Neurotic excoriation complicating superficial parotidectomy. Br J Oral Maxillofac Surg. 1993;31:41-42.
8. Brown JS, Ord RA. Preserving the great auricular nerve in parotid surgery. Br J Oral Maxillofac Surg. 1989;27:459-466.
9. Converse JM, ed. Reconstructive Plastic Surgery. Vol 5. Philadelphia, Pa: WB Saunders Co; 1977:2534.
10. Strong EW. Book review. Head Neck Surg. 1986;9:134.
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